Evaluating Light Fittings to use at Home
Great lighting design starts with understanding how light fittings behave.
One of the greatest challenges designers face in evaluating lights is that every manufacturer formats their data differently; and not all data provided is 100% true! Some of it is very glamorous marketing dressed up to look like facts.
To quickly see past the marketing and get to the most important data, I offer you 6 key measurements of light behaviour to effectively compare light fittings.
My advice can be used as a guide for residential lighting design, and as an extension or a starting place for hospitality and retail lighting. Of course, working with a professional lighting designer is always recommended, but knowing how to evaluate light fittings is valuable for everyone.
SIX key measurements of light quality:
LUMEN OUTPUT – (LM)
BEAM ANGLES AND FIELDS (°)
COLOUR RENDERING INDEX – CRI (RA)
COLOUR TEMPERATURE - (CCT)
WATTS – (W)
GLARE – (UGR/VISUAL TESTING)
With these 6 measurements, you can quickly gain an understanding of a light’s performance which will then allow you to easily evaluate if it’s a reasonable alternative to another known light fitting.
Ultimately nothing beats seeing a working sample and testing your sample in a dark room will let you know if you’re getting the light you want or not.
1. Lumens (lm)
In simplest terms, Lumens is the measure of how much light is coming out of the light fitting. That’s it!
If you need 150lm, then 800lm is not an alternative – regardless of the fact that you can dim the light.
Alternatives and off-spec’ing are a fact of light. There are many “experts” in any construction project confident that they know how best to save a client money by dumping those “silly little lights” in the design. But if the swaps are not made with consideration of the intent, it is never going to create the light you are expecting from your design.
It’s also important to know that 500 diffuse lumens are NOT the same as 500 directional lumens. Diffuse lumens spread in all directions and come “softly” out of a light fitting. Directional lumens are aimed in a direction and so travel further in that direction creating a more noticeable light effect. The connection between beam angles, lumens and light directionality are important for keeping the finesse in your lighting design, as replacing a directional light with a “soft” light – or vice versa – is most definitely not going to create the same effect.
The most common question we hear is, “Are you sure it will be bright enough?”
The quantity of lumens you need to a room is determined by the light levels you are trying to achieve, as well as the colours and reflectivity of the space, directionality, mood and function.
As a starter: If you want a small highlight, then you may only want 150 – 200lumens. If you need functional general light, you’ll likely want 600 – 800lumens. If you’re planning to use indirect light to create a bright room, then you might need 3000 lumens or more from your indirect light fitting to compensate for the lost light reflecting off the ceiling.
Ultimately a great design will use a combination of types of light, and strengths of light to create layers and balance in a room.
2. Beam Angles
Simply – what “size” is the beam of light from the fitting, or “how broad or narrow a space” is the light going to cover.
Anything over 40° is generally going to be glary, so it is best to avoid any directional light with a very wide beam. Often very wide beam lights are used when a ceiling is to be filled with downlights for “general lighting”. If you’re on this path, then try re-thinking your lighting design before you end up with ceiling acne! A professional lighting designer can be great support for suggesting different ways to light a room.
Narrow beams, (10° up to 24° is usually considered narrow), are useful for bringing light down from high ceilings, and for creating dramatic features.
The first step is to check the light fitting data for beam angle information, however in my experience, you need to see a working sample to be sure. Or you can ask the supplier to take a photo of the light grazing hard against a wall so you can see the beam and the field.
When it comes to creating a highly specific effect with your light, whether the beam is sharp or soft, wide or narrow is very important. With narrow beams we often see poor beam control, and that can steal the drama you are trying to create. With light, it’s important to know what you’re working with!
3. Colour Rendering Index (Ra)
Colour rendering is a measurement that many people don’t know about and is far more important than most people realise! It wasn’t a factor in the type of lighting used in homes prior to the transition to LED, but it is now one of the most important metrics for understanding the quality of light.
For the simplest check that you’re on the right path with the quality of your light – CRI 90 or higher is our benchmark.
In homes, we recommend light be no less than Ra 90+ in the living spaces. With TM_30 colour measurement reports you can dive into all sorts of amazing detail about the fidelity and balance of your colour, and you can even see if the light skews pink or green – but that’s a topic for another day.
Usually, people only think about art and soft furnishings when they consider colour, but did you know that each of us reflects colour? We all reflect different colours from our skin.
This means that if we are in poor quality light, we’re likely to look green, or grey – or any number of colours that effectively make us look unwell! Making sure the lights you use are going to render the colours of your body, your room and your interior design is critical to ensuring that your spaces feel crisp, welcoming and “right” when you turn on your lights.
4. Colour Temperature
What colour does your light appear to be when it’s on? Warm/golden or cool/blue?
That’s the colour temperature.
Across the globe we all have different requirements and norms for our preferred colour of light, however in our homes we aim for a consistent 3000k “neutral warm white” – light that is in essence white but is slightly warm.
In cooler climes, warmer light is often preferred in the home, closer to 2700K. Still a quality white light, but with a golden warm hue – definitely not yellow. Often our decorative lighting will be this warmer colour, combined with the 3000K general illumination.
Ultimately, the colour of light you choose is up to you – but here’s the important part – do NOT mix warm and cool!
Rangehoods are the killer for this in homes – every light can be perfect, but if the range comes as standard with 6000K cold white then suddenly we have a spaceship in the middle of the kitchen every night before dinner!
Paying attention to your colour temperature matters.
5. Watts
How much power does the light fitting use?
Watts used to be our key selector for lighting at home. It was how we gauged the “brightness” of a light. With LED, it’s not as useful – what really matters is your lumens.
That said – you want to make sure you’re being ecologically minded, so keep an eye on the watts and make sure they don’t get too high.
In Australia, our home building regulations require no more than 5W/M2 in a home, which keeps a lid on energy consumption. At MINT, our designs usually sit between 2.5 – 3.5W/M2 – that is an energy calculation that includes every light source in the home, not what is being used at any given moment.
6. Glare
When you turn on the lights and flinch – that’s glare.
It is the trickiest measurement to evaluate when reading data from a manufacturer.
Some manufacturers will provide a UGR – Unified Glare Rating – but honestly, the way this is calculated makes it debateable as to whether the information is accurate or useful! It is, however, a handy data point to get you started.
Just like beam angles, the only real way to know the glare is to see the light turned on.
At MINT, we have a rule – if a directional light has a diffuser, we won’t use it. NO PANCAKE DOWNLIGHTS!!!!
I have no idea why people insist on making these awful pancake downlights, but they do, so we have to talk about them! As soon as you diffuse a downlight you end up with a hideous glary light in the ceiling that does nothing for the room – often barely even pushing enough useful light into the room to read at your tabletop.
I understand why they are used everywhere (cheap, easy to install, hide bad plaster joins with bad light, did I mention cheap?) but they are simply awful to live with, and I would love nothing more than to never see another one in a home ever again!
If you find the information for each of these 6 key indicators of performance and behaviour for every light fitting you consider in your home, you’ll be well on the way to getting control over your light and crafting a beautiful experience at the flick of a switch.
MINT lighting experts LOVE this kind of detail and have years of experience with choosing great light fittings. We are here to help – so if you’d like a professional to take care of your lighting design, get in touch!